Pulse forming apparatus



Sept. 26, 1961 o. H. wlNN PULSE FORMING APPARATUS T DI 1 U 1 0 AC N .t W J1 lOhm N. mw J c .mm T N ,Uv wm f Fl m E G s H u H w N A VII V W EMM ER h Slo T VE S S Nx LMW DI NV ...In A Mlle URT AU lll 2 PME: 0m L GM c. d N CAW Emo l l G ,v 1l f Y n j B 'u 2 GW 2 a V Em .umm

URT p u l..\|. m o y F G m 6 #TR 5 E O w WF A 6 .m M 2 w m Alrtmzmo R r F S uu .a S M w m n H F P 3 Sept. 26, 1961 O. H. WINN PULSE FORMING APPARATUS Filed March 26, 1956 FIG.4.

2 Sheets-Sheet 2 LOAD CIRCUIT INVENTOR OLIVER H.W|NN,

HIS AGENT.

v rates.

United "States n Patent 3,002,113 PULSE FORMING APPARATUS Oliverv H. Winn, Whitcsboro, N.Y., assignor to General Electric Company, a corporation of New York Filed Mtr. 26, 1956, set. No. 573,903 3 Claims. (Cl. 307-106) This invention relates to signal processing systems and particularly to an arrangement for providing recurrent pulses. v

In the field of obstacley detection, industrial timing controls, etc., a need exists for generating pulses of predetermined shape at selectable recurrence or repetition Priorarrangements for fulfilling this need have either required a relatively complex and expensive apparatus or exhibited a degree of unreliability, instability and inffexibility which was not always tolerable.

Accordingly, it is an object of my invention to pro- A pulse generating circuit constructed in `accordanceA with one embodiment of the present invention comprises a plurality of energy storage networks coupled to a pulse forming network by saturable inductors. saturable inductors have an inductance which`-varies rapidly in responsek to a predetermined energy condition in the energy-storage network. Energy is supplied to the energy storage network and 'means are provided for de'- In accordance with another embodiment, means are provided to allow selection `between several desirable pulse shapes and repetition frequencies. f The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with fuitherkobjects and advantages thereof, may best be understood by reference to the following descriptionv taken in connection with the accompanying drawings in which:

FIGURE la is a schematic diagram of a signal shaping network providing an output pulse repetition frequency twice that of the source frequency; FIGURES of the circuit shown in FIGURE 1;

' signal storage.

tor which is adapted to integrate the positive going volt- ICC waves 2 supplied by a source 3. Transformer 4 operates' K to transform the voltage available from 3 to the desired output operating level across the secondary winding 5. Linear reactor 6 and capacitor 7 are dimensioned to be resonant at the source frequency f for efiicient Element 8 comprises a saturable reacage appearing across the capacitor 7 and to change its impedance abruptly when the integrated voltage reaches a predetermined value. The characteristics of a core of a saturable inductor suitable for use in such application is shown in FIGURE lb wherein magnetizing force f yis plotted as abscissa and ux density as ordinate.

saturable inductor is dimensioned so that saturation,

The

associated with minimum impedance of the reactor, occurs approximately at the maximum energy storage oli the storage element, capacitor 7. The inductance of the saturable reactor 8, while it is saturated, determines how sharp the succeeding wave developed across capacitor 9 becomes. In a similar manner the saturable reactor 10 operates at a predetermined time to transfer the voltage stored in capacitor 9 into capacitor 11. In one embodiment capacitors 8,y 9, and 11 were dimensioned to be the same and the saturable reactors dimen- The ysioned to provide the desired wave shape improvement;

The 'constants of each of the succeeding network portions comprising a saturable reactor and capacitor were adjusted such that the resonant frequency improved 20u, where n is the number of network por-tions employed in the pulse shaping network.

The l-ast discharge by saturable reactor 12 occurs into the pulse forming network 13 which may be of conventional form such as an artificial delay line for modifying the available wave shape to a suitable form for application to the load circuit 15. `In the embodiment of FIGURE 1, the saturable reactor 16 operates effectively as a high impedance, or open switch -to isolate FIGURE 2 is a schematic diagram of a modification l of the circuit of FIGURE l used Supply;

FIGURE 3 is a schematic diagram of a modification of FIGURE 1, using saturable transformers;

FIGURE 4 is a schematic diagram of the circuit of FIGURE 3 with a three-phase delta supply;

FIGURE 5 is a schematic diagram of a modification of the circuit shown in FIGURE 4 for a three phase Y Supply; 1

FIGURE 6a is a schematic diagram of a modification of the circuit shown in FIGURE 5 for producing two selectable pulse widths and repetition frequency; and

FIGURE 6b represents operating characteristics of a portion of the circuit shown in FIGURE 6. y

Referring to FIGURE l -there is shown one embodiment of applicants invention wherein an output pulse withr a three-phase the load circuit while the preceding networks are being charged and operates as a low impedance, or closed switch when transferring the shaped pulse 1 to the load circuit, which can be the primary of a magnetron-pulsing transformer.

In order that the output pulse delivered to the load circuit is of a higher repetition rate than thatof the frequency of wave 2, the secondary winding 5 is provided with a grounded center tap 16' and a series of reactorcapacitor networks similar to that previously described.y The linear reactor 17 and capacitor 18 are resonant to the frequency of waves 2 and operate in a manner similar to that of elements 6 and 7. The saturable reactor 19 operates like reactor 8 to transfer the integrated voltage developed across capacitor 18 at the proper time into capacitor 9 whereupon it is successively transferred down the described reactor-capacitor circuits and pulse forming network to the load circuit 15. It should be noted that all of the saturable reactors were adapted to operate only on the positive going voltage cycle. Accordingly, the reactors 8, 10, 12 and 16 operate during the first half l cycle of the output voltage developed across the secondary winding 5 whereas reactors 19, 10, 12, and 16 operate during the succeeding half cycle of the output voltage developed by the transformer 4. The shaping of the pulse and the increase in frequency is illustrated by FIGURE lc y wherein voltage is plotted as ordinate to a common time 1- is derived for each half cycle of the alternating voltage identical with those at inductwr 6 and capacitor 7 except tliishifted'intimeby an interval corresponding td one-half cycle of the impressed A.C. wave V. The result isgthat awave similar to Vf appears acrosscapeditori.:9n cycle fs'o'v'thatv the resulting'recurrencetrate"ef S t the' load isfrwio'e th. fioqoool. -ofliho apotffoltv.

gFRefei-ring -to FIGURE 2a ,furtherrembodilnjienth of *the* inyeiitfin is' shown for deriving threemoutputhpulses. for

` 'cycle of thefreduencyoffthe input voltageeource 10 Thel- :threegphase .transformer Z1 transforms the ont-l '.voltage from source'gilrtosthe desired operating leYel.

e output yfrom source Zit is atthe proper leyel, tite transformer can Abe omitted.-` The linearreaeto'rs ZIZHandf. thfcapacit'ors 23 each associated'lwithua respective second- 15 winding of the transformerZ'il, operate as previously described in FIGURE l@ The reactors 24', 24J and 247' operateduring their respective-positive goinghalf cycles toftransfer the integrated yoltage'.deyelopedlacross their y associated capacito`rs'2f3, 23,7, andvr23f tothe saturablei 20 rea orf-'capacitor chain 25e-218 .feeding` the 'pulsevforming nef rk'29 andthe load circuit Saturable reactor Si ates'eectively asa switclras previouslydescribed.Av It ispbviousto those skilled in tlleart that the principles described with respect to FIGURES 1*andnucaunsbe einv 25 plyedlfor use lwith other. multiphase systems using diierf. e e nsformer secondary conne'ctionsvitira threeiph" It' Yshould be notedr'tliat each the saturable Vre-VA.

if? e ma we onyhaieloe .ofthe averageolfpit. daisies@ each. duelli/fires .3o atone thirdfthe output r'e'p'etition'frequency. f

FIGURE 3 shows'an arrangementforude'riving snbstan;v tial svin'gsin the number v'of'components employed deriving the desired Adegree vofwwave shaping. 4 The Acircuit utilfiesfsaturating transformers .in placepf thereactors 35 ply.Y l'ousv described. The saturatingr transformers 32 and v 33' riie'fthetwolfold purpose of theyoltage transformaas, pulse shaping Itshouldbewnoted thatv the unsaturated impedance` ofseachh'ofgthe transformers: 32 4.35 and 33', '34'.y and 35 is reaterrthan its saturated 40 impedance and that'- in itsunsaturatedlcondition tlfte` pedanceof each. transfrmer is smaller'lvthn the unsna'tu;VV rated impedanceof vthe preceding' transfornlierA of, the` szand similarly .the'inipedancegof.eachA- transform ru during its saturated conditionis smaller tiratitheunsatul` rated impedanceofthe followingr transformer giri the series. The .transformer v32"v is diniensioned tosaturate wher-riga suA cient.yoltage, available at'itsiin'pi'it terminalsfhas beenfl integrated to cause the transformer .to'saturategat' which. time its impedance `is muchflessv than that of-the. subcceeding transformer. which stilll is iny the .unsadlrated state Y' The. inductance of. the` t'ansforrnerfjn its; satu-` rated condition;and. the eiifectiie-k inductance of `trans-A former 34 in itsA unsaturated gconc'iition.V t'ogetherL with the. 'p capacitance,determines the risey time ofthevoltage-` deyeloped acrossy the lprirriary'fof the. 'saturable-.transeformerti. i Y

Iii a'manner similar to that previously described, each` ofthe succeeding transformersfi and SStransfer thefin-` tegr'ated voltage developed f across its windings tothe succeeding saturable reactor| stages, the pulse forming. net'-A work 37 andultimately to the load 4circuit 38.5 In this embodiment is shown an arrangement for-rapid discharge-r ofa delay time type ofpulsefor-ming network` Ain a'saturable indnctor. Ina manner, similar to. that described with respect to.FIGURE l, thesaturable transformer l32v andfcapacitor A36 operate during the alternatefhalfqcycles .Y ofrgtlhesource 3 totransfera shapedpulse to the succeeding Asaturable transfoirnersdand .35.:5 'Ihshnear induetailcosfgifand lare proyidedto facilitate suitablewas@vv shaping of .the input wave before al transfer into thel susceeding saturable reactor stages.

FIGURE 4 operates in a sirniiar manner while emr.; ploying a three-phase.deltafinput. FIGURE 5 shows-.a Similar arrangement Usines throo-Pllasof-npot@ 75 The same principle can be used for 4, 6, 12 etc. phase systems using different transformer secondary connections:

FIGURE 6a illustrates angembodiment of the invention whereby a selectable pulse rate integrally related to the frequency of the input source may be derived by utilizing commonlelements. 'I'hree-phasei--pwen is supplied over leads 60, 61p; anfing.v Solenoid 63 controls switch@Y contactors 6ft t'lnjpugljlM 69.1 When the contactors lare in the position shown, the supplied poweris delivered to the saturable transformers 70,71 and 72 connected in a delta arrangement. Whonoloaos. 63;. is .oneraiaed,..power..to satiltlo transformers.. 70 .and 72.. are out or 'by move.. ment of contactors 64' and 65; At the same time,g qthje caraofanoabotwooo successivo @Mutable y.tra11S.fr. rm.o.r.s are ooasod by the. additional capacitors 73 :and 74, 75ans.. 76, oonoeotod in. Parallel. u'ihrhonormal .Coupons oanaoif. tors 77, 78 and 79 respectively, The additional capaci-y tance increases the pulse .widtl1 The lngerM pulse Aata`r lower repetit-ion frequency. is; desirablekforwexample"in long -rangeoperatiOn of radar, apparatus.;y Wnenah repetitionfrate is desiredLthc solenoid is actiyatedhygiying three-phase operations `and` thereforearepetiti nwfequency oflthreetimes that of assodato@ Wifl1...1ooa rasofororstioo. The. shorterand... longer pulses are illustrated in FIGUlE 6b as cuiyes ,..90.f and, .91 .rosnootvolyowhich.iS-.plotted as. abseits@ mayonesasorointo..

'It' willbo. .recoenized-gby .those .Skillodrn .the art .that bias of the cores of certain'reactors in thecircuits may-r bsrnossssary- The bieny oan...,be .applied by @separate D C.` winding; Such windings'are notshowninthewim, feft 0.,..S111l11f.y ioamaorevviss .and .dosorpton...1L

Wh. Spoooolabodimant havo booahownno def... Scribe booadortoodihat varousmod' foatioos,` yet,bo...,doY.So.diby those Skilled inthe Whiol1 wi1.1ro1i1l?o iythe. Principles. ortho :invention and-1 foon@ ...in .ih waaruit .anidtsooizothoreoi What .1.o1ai m as non'. and dosirlo, to Seome .by .LettersIA Pateotofgtho United.;StateS-:is=..`

1- .11.1. combination@ .soorooof alternating. electric vole..- age, a transformer havingua primarywinding and a cen t e r-. tapped-seconder..winding; said. ,Secondary iiinciineharingfa -lrst and .Soondorrnnal.at-.opposite ndsfande: third terminal intermediate-saidlends, meansmcouplingg said fsouroeto saidrrimory windings-H rof andooond tuned.: circuip*coniprisinigrV` atserially coupled inductanceg and .Caraoitaooodiuonsionoo robo-resonant at tho. :fre: quencyvof ,said source, .saidrfnst tuned circuit,i being 1 coupled. betweensaid -rst and thirdA terminalsuon said,l secondary.- winding, isaid secondk tuned circuitM being; coupled between said second and third terminals on said secondary winding, a rst satnrable inductor, a pulses` shaping networkrisaidsaturable Ainductor 1 and said pulse Shaping. network being serially Connected, means cooplinei. saidv iirst vsaturable inductor v and said pulse shaping net-y worlr `across saideapacitance in *said first tuned circuit, a` second saturable inductor, said second saturable inductonl and said pulseshapingnetwork being serially connected, meanscoupling said second saturable inductoryandrsaid pulse shaping network across said capacitance insaid. Seooootunod circuit.. an-oufpuocircuit, means .coupling saidl output circuitjtonsaidi pnlse shaping network.v

2.: Ir 1 com`bina itiona source of phase alternating yoltage havinga .iirpsthsecond'andthird tcrminalsg-a first, second andfthirdV-f-saturabletransformer, means coupling said vfirst satlvlrablei transformer across said first and second; terminals of said source, a first operable switch-,meansl Coupling.; Said .;Sooond. saturablertraosforsior across. Said rstsft-hr. k.tortllillolsof Said. Source, a Second operablef switch meanscoupling-said third saturable transformer; across said; second rar1-d thirdterminals of saidA sourcega pulse forming network,l saidnetworkj comprising a plusL ralityof saturablemtransformers, saidj transformers -being coupled `together by a first capacitive-means, a third; operable snitohnleans adantedtorarnsaid first: oapaoitire'-,

5 l t means, a second capacitive means ycoupling said pulse forming network to said first saturable transformer, a fourth operable switch means adapted to vary said second capacitive means, a third capacitive means coupling said pulse forming network to said second saturable transformer, a fifth operable switch means adapted to vary said third capacitive means, a fourth capacitive means coupling said pulse forming network to said third saturable transformer, a sixth operable switch means ladapted to vary said fourth capacitive means, means for operating all of said operable switch means simultaneously, an output circuit, means coupling said output circuit to said pulse yforming network.

3. In combination, a polyphase source of alternating voltage, a pulse shaping network, said pulse shaping net'- work comprising Ia cascaded plurality of energy storage and transfer sections to store electrical energy and to transfer said energy in a shorter time than that required for storage, each of said sections comprising a saturable core transformer and a capacitor, time shortening means in each of said sections to shorten the time required for transfer of energy comprising means to change the value of said capacitance, a irst saturable core transformer having a substantially rectangular hysteresis curve coupling one of said phases to said pulse shaping network, coupling means simultaneously operable with said time shortening means for coupling each of said phases to said pulse shaping network, said coupling means comprising y a saturable core transformer including said first saturable core transformer and having a substantially rectangular hysteresis curve associated with each of said phases, a load circuit, and means to couple said load circuit to the last of said cascaded sections in said pulse shaping net- Vwork.

References Cited in the le of this patent UNITED STATES PATENTS 1,180,800 Taylor Apr. 25, 1916 2,166,785 Aigner July 18, 1939 2,659,008 Floyd Nov. 10, 1953 2,692,954 Young Oct. 26, 1954 2,727,159 Sunderlin Dec. 13, 1955 FOREIGN PATENTS 154,760 Australia Feb. 1, 1951 666,574 Great Britain i Feb. 13, 1952 

